Lead acid batteries include a plurality of closely spaced positive and negative plate members that are disposed in an electrolyte such as sulfuric acid.
Separator members are disposed between each pair of contiguous plates to prevent them from contacting one another. The separators must be constructed to allow electrolytic flow within the battery, i.e., the separators must not prevent the chemical action of the battery that produces the current. Lead acid batteries are often used in environments where high vibrations are experienced. Thus, separators must be capable of absorbing vibration. Many battery separators are known. For example, U.S. Pat. No. 3,351,495 to Larson, et. al. shows a battery separator for a lead acid battery where the separator is made from a mixture of high and lower molecular weight polyethylene to form a flexible separator.
Another battery separator made from a mixture of high and lower molecular weight polyethylene is shown in U.S. Pat. No. 4,190,707 to Doi, et. al. Moreover, U.S. Pat. No. 4,731,304 to Lundqist also discloses a mixture of high and lower molecular weight polyethylene for forming battery separators.
Other U.S. Pat. Nos. of interest include 4,024,323 to Versteegh, 4,588,633 to Kono, et. al., 4,283,442 to Machi, et. al., 3,544,384 to Sundberg, 3,228,802 to Rabl, 4,024,213 to Honda, 4,234,623 to Moshtev, 3,787,240 to Gillman, 4,201,838 to Goldberg, 4,626,468 to Sundet, and a Japanese patent No. 53-41112.
The electrical resistance between the plates of a battery increases directly proportional to the square of the distance between the plates, i.e., the inverse square law applies to the current produced by the battery. Current produced drops in proportion to the square of the distance between the plates.
More specifically, the following data has been compiled for prior art separators which are fifty percent porous and which have seven ribs;
______________________________________ Equivalent Electrolyte Plate Spacing Separator Space Spacing Squared Mass Available ______________________________________ .045 .002 .020 .025 .040 .0016 .020 .020 ______________________________________
There is a need for an improved separator that can reduce the plate spacing substantially without adversely affecting battery performance, but the prior art neither teaches nor suggests how plate spacings could be reduced any further without affecting battery performance.